1. Field of the Invention
This invention relates to preparations for treatment of fibers which are especially suitable for the treatment of synthetic fibers, e.g., polyester fibers, which are obtained by melt spinning.
2. Description of the Prior Art
Polydimethylsiloxanes are used for the preparation of melt spun fibers. These polydimethylsiloxanes, usually called silicone oils for simplicity's sake, impart to fibers treated with these oils, a lower coefficient of friction, especially at high yarn winding speeds wherein this friction coefficient has a small temperature dependency. Moreover, silicone oils are extraordinarily heat-resistant and have a low viscosity-temperature coefficient.
The treatment of melt-spun yarns with such preparations or "finishes" directly after their production renders possible the subsequent stretching and texturizing processes of said yarns. For such purposes, the preparation has to be effective as a lubricant and antistatic agent. In thermosetting treatments of the yarn, finish components are often transferred unintentionally onto heating units and are subjected to heat in the unit for a long time. Therefore, the preparation has to be thermally stable. The preparation transferred on the heating units should, if possible, not turn to gel, turn yellow or evaporate. It is most important that it will not turn to gel.
At the same time, the finish components should be as compatible as possible with each other. This is especially a great problem with regard to the compatibility between polar, tensidic components, which are primarily responsible for the antistatic efficiency, and the non-polar methylsilicone oils, which are mainly responsible for the lubricating properties. The compatibility of the preparation components is especially important when the preparation is to be applied to the fibers directly in the form of an oil, i.e., without being previously dissolved or emulsified.
The compatibility of methylsilicone oils especially with paraffinic substances can be improved if the methyl groups are partially substituted by longer chained alkyl groups. The resulting oils, however, no longer possess sufficient thermal stability. Moreover, the viscosity-temperature coefficient of such modified methylsilicone oils rises significantly.
The partial substitution of methyl groups by phenyl groups also leads to products with higher viscosity-temperature coefficients which results in decrease in the lubricating properties.
Certain aryloxy substituted silicone oils turn out to be especially suitable components for melt-spinning as compared to the oils used in the art. The compatibility of these aryloxy substituted silicone oils to other common preparation components has been surprisingly improved. These aryloxy substituted silicone oils have exceptional thermal stability and they give melt-spinning preparations remarkable lubricating properties.
Moreover, these aryloxy substituted silicone oils can be produced easily and relatively inexpensively. German Offenlegungsschrift 26 45 459 describes a textile fiber preparation which is characterized by a content of 1 to 99% by weight of compounds of the general formula ##STR2## wherein R' is mono-, di- or trialkylphenyl, the sum of carbon atoms in the alkyl portions of the phenyl group being 6 to 12, or trimethylsilyl,
R" is an alkyl group with 1 to 16 carbon atoms, wherein the carbon chain may be interrupted by the group ##STR3## and/or wherein the residue is M.sub.a --O--R"", R"" being a mono-, di- or trialkylphenyl wherein the sum of the carbon atoms in the alkyl portion of the phenyl is 6 to 12 or is the residue ##STR4## R'" is an alkyl group with 1 to 16 carbon atoms or ##STR5## M is an alkyl group with 1 to 3 carbon atoms and n is 2.5 to 15, PA1 m is 0 to 5, and PA1 a is 0 or 1, PA1 n has a value from 3 to 30,
the average molecule having formula (I) has 5 to 30 Si-atoms, of which at least 20 mol% are Si* atoms and 0.5 to 10 are mono-, di- or trialkylphenyl, and 99 to 1% by weight of known or conventional components.
This formula represents the average formula of the polymer mixture.
The above-mentioned known textile fiber preparation as described in German Offenlegungsschrift 26 45 459, has been demonstrated in practice. However, the compatibility of such compounds with tensides, and particularly with cationic and anionic tensides, is sometimes too low. Moreover, the viscosity of this preparation is too high which results in difficulties when these finishes are used with very fine textile fibers.